Slave network slave processing method and apparatus information collection method

Abstract

A network system is constructed by connecting a safety PLC constituting a master unit and safety slaves 2 to each other through a safety network 3. The safety slaves each have a device information storage unit 25 for storing individual information and status information of the safety devices connected. The individual information is acquired and stored in advance, while the stored contents of the status information are updated based on the result of monitoring the status of the safety devices in operation. These processes are executed by a MPU 23. In response to a request from the safety PLC, the device information stored are transmitted, so that the safety PLC can collect and manage the device state as well as the normal state of the slave units.

Description

TECHNICAL FIELD [0001] The present invention relates to slave units and a network system as well as a slave unit processing method and a device information collecting method. BACKGROUND ART [0002] In the programmable controller (hereinafter, referred to as “PLC”) used for the factory automation (hereinafter, referred to as “FA”), the on / off information is input from an input device such as a switch or a sensor, and the logic operation is executed according to a sequence program (also referred to as the user program) written in the ladder language or the like. In accordance with the operation result obtained, the signal of on / off information is output to an output device such as a relay, a valve or an actuator thereby to perform the control operation. [0003] The PLC is connected to the input device and the output device either directly or through a network. In the case where a network system connected by a network is constructed, the on / off information is transmitted or received thro...

AI Technical Summary

Benefits of technology

This patent describes a network system that allows a controller to connect to slave units and collect information about the devices connected to the slave units. The information is stored in a database and can be transmitted to other devices through the network. This system can help quickly identify malfunctions and determine the cause of the malfunction by analyzing the device information. It can also help prevent malfunctions by monitoring the device status and providing notification when the device reaches the end of its lifespan. The patent also describes a method for collecting and storing the device information, as well as a monitoring device that can acquire the device information through the controller or directly from the network. The technical effects of this patent include improved device monitoring and management without the need for physical inspection and faster maintenance job resolution.

Problems solved by technology

This maintenance is complicated, and makes it difficult to take the necessary action quickly.

It is still more difficult to monitor the life of the input and output devices connected to a slave unit from PLC, and therefore, a malfunction or fault is often handled only after it has actually occurred.

Even in the case where the installation site of a slave unit or a device connected with the slave unit is visited upon occurrence of a fault or the like, therefore, the status cannot be easily checked if the device is small or installed in the depth or behind other devices.

As a result, the status of these input and output devices cannot be accurately grasped, and therefore the cause of a malfunction or fault may not be analyzed sufficiently.

Further, in the case of a network system having security means, the safety devices, though high in reliability and redundancy, are often shorter in life than the devices making up the conventional normal network.

Once a malfunction of these safety devices occurs, it leads to the stoppage of the whole system, and therefore has a great disadvantageous effect on the whole system.

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